During this time of year, the sun is high enough in the sky (typically between about 10 a.m. and 2 p.m.) to activate your skin’s natural production of vitamin D. So, do your best to make it outside to soak up some mid-day sunshine whenever you can.
Your skin conducts this form of photosynthesis when the right wavelengths of sun pass through the atmosphere and reach exposed skin.
So how much — and how fast — can your skin actually make vitamin D?
I see natural “know-it-alls” and “johnnie-come-lately” physicians throw out numbers with very little science to back it all up. But coming up with an accurate answer involves chemistry, geometry, physics, optics, climatology, geography, and meteorology.
Consulting the real experts
To find out exactly how much and how fast our bodies can produce vitamin D, I knew I needed to consult with some professionals who are more well-versed in the physical sciences.
I thought about asking a physicist, if I knew one with some free time. But the really reputable ones are actually few and far between. And they’re busy investigating the deepest secrets of the cosmos. (Or sometimes contributing a chapter on quantum biology to a new edition of one my medical textbooks.)
There a few celebrity physicists I know who make a living talking at length about quasi-scientific issues with a clear, politically correct slant. But — like Neil deGrasse Tyson, the insufferable fool from the Hayden Planetarium in New York City — they aren’t very good at actual science.
I decided to ask some engineers who I personally know have been pondering the question…
According to one of their calculations, when the sun is 50 degrees above the horizon, your exposed skin can make 1,000 IU of vitamin D in just 22 minutes. (Note: 45 degrees is half-way above the horizon, and 90 degrees is directly overhead.) And when the sun is higher, at 67 degrees, it only takes exposed skin 12 minutes to produce 1,000 IU of vitamin D.
The sun only ever reaches 90 degrees, directly vertically overhead, in the tropic zones, to either side of the equator between the Tropic of Cancer in the north and the Tropic of Capricorn in the south. On the equator, the sun is directly overhead at noon on the vernal equinox (which was on March 21, 2018) as the sun heads over northern hemisphere, and again on the autumnal equinox as it heads back over the southern hemisphere.
Of course, several other atmospheric factors influence the rate of vitamin D production in the skin. Including altitude, cloud cover, ozone depth, and reflective surfaces around you (also known as “albedo”) such as the sea, sand, and rocks.
In addition, physiologic factors influence vitamin D production in the skin. This includes your skin pigmentation, coverage from your clothing, the amount of vitamin D precursors present in your skin, as well as your skin’s oils and water content.
Furthermore, individual “genetic” variations influence your vitamin D production. For example, doubtless you’ve noticed dramatic differences between how you and another person respond to the same sun exposure? Always, always pay attention to what your own skin is telling you.
Boost your natural D production this summer
Instead of the blanket, one-size-fits-all recommendations doled out by mainstream doctors or natural health know-it-alls, observe how your body reacts to sunlight and act accordingly.
To determine the ideal amount of time you should sunbathe, sit outdoors one afternoon and note how long it takes for your skin to slightly flush. (A quick “sunburn self-test” you can conduct involves pressing down on the top of your forearm — if your skin appears lighter after you touch it, you’re getting flushed.)
I recommend sunbathing for half that amount of time. Of course, as your skin pigmentation deepens, you can gradually increase the time you spend each day in the sun. You can also:
- Keep as much of your skin exposed as possible. (From what I’ve seen during Spring at my home in Florida, the women on spring break here seem to have that base covered…or uncovered.)
- Look for bathing suits, t-shirts, and shorts “engineered” to block only about 50 percent of sunlight. (Regular clothing blocks about 99 percent of the sun’s rays.)
In addition, I recommend taking a vitamin D supplement. We’ve made a lot of progress lately to better understand the dose you really need to achieve the optimal blood levels of vitamin D, which protect against cancer, dementia, diabetes, heart disease, and other chronic conditions.
I suggest a daily dose of 10,000 international units (IU) of vitamin D3 — even in the summer, as most people are already very insufficient or deficient. Now, I know, that dose in IU may sound large. But in fact, thousands of international units of vitamin D translate to just hundreds of micrograms.
(I’ll explain this in detail — and also reveal how mainstream medicine is attempting to use this confusion to their advantage — in the next issue of Insiders’ Cures, my monthly newsletter. Not yet a subscriber? Simply click here.)
Stay tuned and in the meantime, don’t be afraid to soak up a little sun.